1. Field
The present disclosure generally relates to techniques for reworking areas of a structure, and deals more particularly with automated production and installation of patches used to rework areas.
2. Background
Composite structures sometimes include localized areas that may not conform to product and/or performance specifications, for any of a variety of reasons. For example, localized areas of the structure may be out-of-compliance because of non-conformities, including without limitation, dents, scratches, gouges, delamination or lightning strikes. These non-conformities may occur during the initial production of the structure, or later, after the structure has been placed in service.
Localized non-conformities may be reduced or eliminated by reworking (including repairing) the structure. The rework/repair process may involve removing one or more layers of material from the structure and then replacing the removed material with a composite patch that is bonded to the structure. In one technique, the edges of the rework area may be tapered or “scarfed” in order to form a scarf joint between the structure and the bonded patch. In another technique, the edges of the reworked/repaired area are stepped in order to form a series of lap joints between the patch and the structure.
The current method of fabricating a composite patch is time consuming, labor intensive and subject to human error. A workman measures the size and shape of each ply of the rework/rework area after material has been removed from the structure, and makes a pattern of the patch. The individual plies of the patch are cut by hand from bulk materials, and then oriented and stacked by hand. These manual steps may allow the introduction of inaccuracies which may make it difficult to achieve a desired fit between the rework patch and the rework/repair area. The consistency of the rework/repair process from one rework/repair to another may vary due to dependency on hand labor to fabricate the patch areas.
Accordingly, there is a need for a method and related rework/repair patch for reworking/repairing an area of a structure that reduces the need for hand labor, improves the quality of the rework/repair patch, and increases fitment and alignment accuracy between the rework/repair patch and the area requiring rework.